Thermostatic apparatus.



PATENTED JUNE ll, 1907.

E. F. WOODMAN.

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Parr-ENT orrrori.

EDWARD F. WOODMAN, OF BOSTON, MASSACHUSETTS.

THERMOSTATIC APPARATUS.

Application filed November Specification of Letters Patent.

17,1906. Serial No. 343,871.

Patented June 11, 1907' To fl/ZZ wtmn/ it ntay/ concern:

Be it known that 1, EDWARD F. OODMAN, a subject of the King of Great Britain, and a resident of Boston, county of Suffolk, State ef Massachusetts, have invented an Improvement in Thermostatic Apparatus. ef whichv the following description, in connection with the accompanying drawing, is a specification, like letters on the drawing representing` like parts.

This invention has for its object the production of a simple, efficient and very sensitive thermostatie circuit-controlling apparatus whereby the condition of an electric circuit is changed automatically by or through the distintegration or fusion of a fusible inember or part of a controlling device when the temperature in the vicinity of the apparatus has risen to a predetermined point.

Apparatus of this character should be so constructed that the operation thereof will be effected in the shortest possible time and at a relatively low temperature, in order that there may be no delay in giving the indication of abnormal temperature conditions in the vicinity of the apparatus.

Various forms of thermostatic apparatus have been devised wherein a joint or connection is made by fusible material used as a j solder to connect two pieces of metal, the separation of such pieces when the solder fuses effecting the operation of the apparatus, but in such apparatus the temperature required to fuse the joint er connection is frequently higher than the fusion-point of the solder itself.

My present invention belongs to the type i of tliermostatic apparatus wherein a fusible material is employed, as distinguished from thermostatic apparatus wherein a more or less volatile liquid is used as the element to he acted upon by a rise in temperature.

ln the present embodiment of my invention the controller for the circuit-changing means includes a member of fusible material, y

which is loosely engaged and enveloped by a vitreous casing exposed to temperature changes in the vicinity of the apparatus, the casing serving to normally maintain the said fusible member in such position that the circuit-changing means is retained inactive.

When the fusible member disintegrates or fuses the controller is rendered inoperative and the circuit-changing means acts to effect an immediate change in the condition of the circuit in which said means is included.

l The construction herein illustrated and del scribed is such that the apparatus is very j quick in its response to a rise in temperature l to the piedet -\,rinined point, and with very j little variation as to the fusing point, using j fusible material having a given fusion-point. j The various novel features of my invention j will be fully described in the subjoined specij lication and particularly pointed out in the j following claims. l, Figure 1 is a diametral sectional view of j a thermostatic circuit-controlling apparatus l embodying one form of my invention, the j parts being shown in normal condition, Fig. 2 is a similar view but showing the parts just after fusion or disintegration of the fusible j member of the controller, Fig .i 3 is a'A separate i view in elevation of the controller and the l inclosing vitreous casing therefor Fig. 4 is a l plan view of the base, showing the chamber j therein, the circuit-changing moans, and a l portion of the controller, one member of the j circuit-changing means being broken oil", Fig. 5 is a side elevation and partial section j of a modified form of base embodying my inj vention, Fig. is a similar view of the base l, illustrated in Figs. .l and 2, and showing a. j modification to be described g Fig. 7 is a diainetral sectional view of the base and the j parts carried thereby, showing my invention i applied to a normally-closed circuit. j Referring to Figs. 1, 2, 4 and 6, l have shown the base o as a circular block of suitj able insulating material, such as porcelain, j having a chamber a/ and an opposite concavity o2 in the outer face of the base, an apj erture of* opening into the chamber and forming an annular seat c4. l The base a fits snugly into a circularly rej cessed holding-plate l), also of insulating niaj terial, and provided with suitable holes to j receive screws s or other fastening devices by means of which the apparatus is secured to l the ceiling or other portion of a room. l An internal annular groove DX is formed j in the wall of' the plate I), to register with a similar external groove (LX on the periphery j of the base (L when the latter is in position, j the opposed grooves forming less than a coini plete circle in cross-section. This groove is i, filled in with plaster, cement, or other suitable plastic material, as at CX, to form a tight joint or seal between the base and its holding plate, and also serving to hold the base in l place without other fastening means.

i The base is provided. with suitable bindlOO ing-posts a5 for connection with the linewires of the electric circuit (not shown) in which the circuit-changinemeans is to be included, the posts being electrically connected in usual manner with terminals within. the chamber a. Such terminals form a part of a circuit-changer or circuit-changing means, such term being used to designate a device or devices whereby the condition ot' the electric circuit can be changed, as for instance from an open to a closed circuit, or vice versa. Herein one of the terminals, as c, is formed as a strip of metal extended from the periphery of the base a inward toward the center' of the chamber o, see Figs. l, 2, aand 6. The other terminal c is herein shown as a piece of elastic or spring` wire securely held at one end on the base, and at its other end bent or coiled to form a depending spiral coil or springl c2, located beneath the free end of the terminal c, Figs. l, 2, 4 and 5. The coil is so wound as to normally expand when free to do so, and its end is adapted to rest upon a bushing d of vulcanite or other heat-insulating material, which I prefer to use, such bushingbeing inserted in the aperture e3 of the base and having a flange d to rest upon the seat a". Willen the coil is free its expansion causes the inner end el' the terminal c' to engage the terminal c, to thereby close the circuit, as shown in F 2, whereas, when the spring is compressed, as in Figs. l and 5, the terminals are separated and the circuit opened.

I have devised a novel and very efficient controller for the circuit-changer, the controller being shown herein as a shank c of still' wire, slightly hooked one end. at c and at its other end havingl an attached enlargement er button ci? of fusible material commonly used in thermostatic apparatus.

The hooked end c is, in use, caught over the free end ofthe terminal cf, F igs. .l and et, and also Fig. 5, the shank c passing through the coil c2 and being long enough to extend through the bushing d, with. the enlargement or button c2 outside of the base. This fusible member c? is loosely inclosed in a preferably glass casing, shown. separately in F 3, and of bulb-like form, having a subu stantially cylindrical neck f and a globular portionj", the latter formingl a shoulder' adjacent the neck, to loosely engage the inember e2 when abutted against it and hold said member in proper position.

In order to assemble the parts shown in Fig. 3 I insert in the casing a sul'li cient quantity of the fusible material, and by means of a flame applied to the bulb 1 soften the material su'lliciently to cause it to form a button, into which the end of the shank e is thrust, and then the button is allowed to cool and harden, a firm and rigid connection being secured between the button and the shank.

| l l i l l l l l W'hen solidified. the button c does not stick or adhere to the bulb, but is absolutely loose therein and unconnected therewith, but as it is ol' greater diameter than the neck fsaid button cannot be withdrawn.

It will be understood that in Fig. 2% I have shown the button abutted against the shoulder of the bulb, as is the case when the parts are in working position.

To apply the controller to the apparatus the base a is removed. from the holdingplatc and the nec'k j' ol' the bulb is slipped through the bushing d, and the spiral spring c2 is compressed until thel hook c of the shank can be caught over the part of the terminal at the adjacent end of the spiral. Thereafter the expansive action. of the spring acts to draw the button ci; against the shoulder of the globular part j" el" the bulb, and in turn the said portion f is drawn against the bushing d, seating thereon and closing the opening into the chamber of the base c.

The shank e is ol.' such length that when in they assembled condition described, sce Fig. l, the terminals c and c are held apart, so that the circuit is open. rlhe base is then placed in the plate b and secured in position, as has been describedl and the apparatus is ready for use when the line-wires or" the circuit are connected with the binding-posts fr".

The bulb is made of thin glass, and can bc easily and quickly produced at a practically nominal cost.

Supposingl the apparatus to be in the condition shown in Fig. l, a rise in temperature adjacent thereto will, when a pre(leterminerl point is attained, disintegrate, or l'use the member e2, immediately loosening the shank e and the spring coil c2 expands and closesl the circuit through the terminals.

inasmuch as the fusible member of the controller is wholly outside the base, and out of contact therewith, it is by its location sensitive to an abnormal rise in the teinilwrature around the apparatus, and the scnsitivcncss and rapidity of action appear to be greatly enhanced by the inclosing casing. While the latter is of glass, and thus is a poor conductor of heat, I believe that .the radiating action 'of the glass serves to concentrate and focus the heat upon the button at, insuring rapid action and great sensitiveness.

'lhe bushing d is preferably used as it insulates the bulb from the base, and thereby prevents any tendency for the heat of the bulb to be conveyed to the base, which, owing to its material, heats Very slowly, cvcn for a very considerable and rapid rise in thc temperature of the air about it.

Wfhen the member or button e 'fuses it drops into the bottom of the bulb, and the latter will ordinarily drop from the base, as the neck of the bulb fits loosely into the bush# ing` d.

In Fig. 5 I have shown the face of the base IOO shaped to form an annular species of guard alo which surrounds the globular portion of the bulb, buty at a sufficient distance therefrom to allow free access of the heated air to the bulb. rl`his guard tends to protect the bulb from an accidental blow which might break the bulb. Otherwise the construction of the apparatus is the same as that previously described.

In Fig. 6l have omitted the coiled spring on one of the terminals, such terminal c5 vhaving in itself sufficient elasticity or spring action to hold the button and bulb in proper working position, the hook e of the shank engaging the free end of the terminal.

By a slight change in the terminals my invention is readily adapted to be used with a normally closed circuit, as shown in Fig. 7.

The spring-acting terminal c6 is above the other terminal c7, the latter being preferably made as a plate or strip of metal, while terminal c is a spring wire. The hook c of the shank e is hooked over the terminal c near its free end, to hold it in contact with terminal c7 under normal conditions. rWhen the button e2 is fused the terminal c is released and springs up into dotted line position, Fig. 7, opening the circuit.

It will be obvious that the circuit-changing means can be made in various forms, for either a normally closed or a normally open circuit, but in all cases the controller is substantially the same, and includes a fusible member unconnected with but loosely engaged by and held normally in position by a glass casing to maintain the circuit-changing means inactive until a predetermined rise in temperature occurs.

The casing which incloses the fusible member of the apparatus acts also as a protective covering to prevent the access of acid or other fumes to the fusible material, a feature of great value in all cases where such controlling apparatus has to be installed in places where such. fumes are liable to occur.

It has been found in actual practice that these fumes act in such a manner. upon fusible material of the class used in thermostatic controllers that the material will crumble and thus disintegrate becoming perfectly useless and requiring frequent renewal.

Having fully described my invention, what l claim as new and desire to secure by Letters Patent is :-f

1. ln a thermostatic circuit-controlling device, a circuit-changer, a controller therefor including a member of fusible material operatively connected with the circuitchanger, an apertured base of insulating material on which the latter is mounted, andv a easing having a tubular reduced portion inserted in the aperture of the base, the casing having a shouldered portion against the interior of which the fusible member loosely abuts under normal conditions, to be held thereby in position te maintain the circuitchanger inactive, said fusible member in turn acting to maintain the casing in position on and external to the base.

2. ln a thermostatic circuit-controlling device, a chambered base of insulating material provided with an aperture, a circuitchanger within the chamber and adapted to be included in an electric circuit, a controller for and operatively connected with said circuit-changer and including a member of fusible material external to the base, and bulb-like glass casing having a neck to enter the aperture in the base, the fusible member of the controller being inclcsed within the bulb and held thereby in position to prevent, through its connection with the circuit-changer, any operation of the latter until fusion of said member.

3. ln a thermostatic circuit-controlling device, circuit-changing means adapted to be included in an electric circuit, a controller therefor comprising a button-like member of fusible material, and a connected shank to co-operate with said means, and an exposed glass casing for and having a contracted portion loosely engaged by said member to maintain it in position to maintain the circuit-changing means inactive until the sh ank and fusible member are separated by fusion of the latter, said fusible member acting to retain the casing in position until the said member and shank are separated.

Ll. A thermostatic circuit-controlling device comprising circuit-changing means adapted to be included in an electric circuit, a controller therefor comprising a button of fusible material and an attached shank operatively connected with said means, an apertured support on which the circuit-changing means is mounted, and an exposed globular casing in which the button is inclosed and loosely engaged and held in position under tensile strain to act through the shank and maintain the circuit-ch anging means inactive until fusion of the button, said casing having a tubular neck inserted in the support and held therein by engagement of the button with the interior of the casing.

5. In a thermostatic circuit-controlling device, a circuit-changer adapted to be included in an electric circuit, a controller therefor having at its outer end a fusible enlargement, a support for and on which the circuit-changer is mounted, and a thinwalled, exposed globular casing of vitreous material loosely engaging and inclosing said enlargement and normally maintaining it in position to retain the circuit-changer inactive, the controller acting reeiprocally upon the casing to normally maintain it in position upon the support for the circuit-changer.

6. A thermostatic controlling device, comprising a chambered base provided with an aperture, an insulating bushing in the aperture, a spring-actuated circuit-changer Within the chamber and adapted to be included in an electric circuit, a controller for said circuit-changer, comprising a shank operatively connected therewith and having a l'usible enlargement at its outer end, the shank passing loosely through the bushing, and a globular glass casing having a cylindrical neck to receive the shank and inserted in the bushing, the fusible enlargement being loosely inclosed Within the external globular portion of the casing and normally maintained by it in position to retain the circuit-changer inactive, the spring action oi" the latter acting through the controller to retain the casing in place with its globular portion pressing against the outer end oi: the bushing, to close the entrance to the chamber ofthe base.

7. A thermostatic controlling device, comprising a chambered base provided with an aperture, co operating circuit terminals Within the chamber, one of said terminals being spring-actuated to change its position relatively to the other terminal, a controller comprising a shank operatively connected With the spring-actuated terminal and llaving a fusible enlargement at its outer end, the shank passing through the aperture oi the base, and a thin glass bulb having its neck inserted in the aperture and receiving the shank of the controller, the Vfusible enlargement of the latter being loosely inclosed Within. the exposed globular portion ot the bulb and normally maintained thereby in position to prevent any movement of the connected circuitterminal, the spring action of the latter pressing the globular portion of the bulb against the outer end of the aperture in the base to close the chamber thereof 8. A thermostatic circuit-controlling device comprising a chambered base ol insulatl l i ing material provided with an aperture, circuit-terminals within the chan'iber, one ol the terminals being shaped to vform a spiral spring at its free end, supported on the base concentric with the aperture, a controller comprising a shank operatively connected With the terminal and extended through the spiral and. the aperture and having a :Fusible button on its outer end external to the base, and a globular casing loosely inclosing and unconnected with the button and having an opening through which the shank extends, the button abutting against and being held by loose engagement Wi th the casing in position to cause the shank to compress the spiral spring and maintain the circui t-termin als separated, the tension oi the spring at the same time acting through the shank and button to retain the casing pressed against the extcri or of the base to close the aperture thereol".

9. In a thermostatic circuit-controlling device, a base having a chamber and an aperture opening thereinto, a circuit-changer Within the chamber and adapted to be included in an electric circuit, a coi'ltroller therefor having at its outer end a liusiblc enlargen'ient, a glass bulb loosely inclosing said enlargement and normally maintaining it in position to retain the circuit-changer inactive, the neck ol' the bulb passing through the aperture in the base, said aperture being closedv by the adjacent globular portion oll` the bulb, and a guard. on the base encircling the bulb to protect the same from breakage.

In testimony whereof, I have signed my name to this specification, in. the presence ol'v two subscribing witnesses.

EDARD F. lOODiNlAN.

Wlitnesses 1 JOHN C. EDWARns, EMILY C. Honcns. 

